The Mash/Sparge Conundrum

I have been brewing all-grain for a couple years now. After a multitude of batches - spent learning and experimenting - I have reached the point where I am ready to gain understanding and insight into every aspect of the beer-making process. Simply, I have become a proud lover of everything beer and I hope to make consistently-delicious all-grain home-brews. And I cannot stress enough the importance of - and my personal desire for - consistency.

As I continue on my quest, I have learned and fully realized that beer-making is a science. There are numerous equations, methods and techniques to the madness. Clearly, brewing beer can be explained in simple terms and executed with relative ease (heck, there are only 4 basic ingredients). However, for those, like myself, who strive for perfection: Brewing beer is an (often sticky) web of variables that go on, and on, and on...

The speckle along the path to beer enlightenment which I need to tackle quickly, and efficiently, is the process of Mashing and Sparging. I cannot count the number of batches of beer I have made, but for one thing I am certain - my mash is never consistent and always lacking in efficiency. I am sure there are many reasons why this is the case, including my custom-made mash/sparge system which eventually needs to be replaced. However, the most important thing that I admittedly lack is - understanding.

A semi-brief description of my mash/sparge system:

I currently use an Igloo "Icecube Maxcold" 15 gallon square roller cooler as my mashtun. I attached a spigot at the bottom of the cooler for drainage. Inside the cooler, and connected to the spigot, is a cpvc manifold with holes drilled in it, also used for drainage. This is the forum I originally got the idea from: https://www.homebrewtalk.com/f51/60qt-ice-cube-mash-tun-build-cheap-simple-144475.

So, I first get my hot liquor up to temp (~165-170 F) while meanwhile preparing and grinding the grains. Once the hot liquor is ready, I pour it quickly into the mashtun with the grains, trying my best to pour the water and grains at the same rate to get a good mix. After this transfer, and some gentle mixing with a brew spoon, the temperature of the mash is typically around 152-156 degrees. I close up the cooler and let it sit for an hour. During that hour it just sits - no recirculating, no mixing. When the hour is up, I open up the spigot at the bottom of the mashtun and fill up a bottling bucket with about 2.5 gallons of wort. I briefly close the spigot on the mashtun, connect a hose to the bottling bucket, and begin draining the 2.5 gallons of wort back on the top of the grain bed. At this point I re-open the spigot on the mashtun and begin filling another bucket with wort. Since the mashtun is draining while wort is being recirculated back on top of the grain bed, a vacuum-like force is created, pulling the wort downwards in hopes of enhancing the grain bed and possibly enhancing the rinse as well. I repeat this "recirculating" process, anywhere from 3 to 6 times, so in the end I will have recirculated about 7.5 to 15 gallons of wort.

At this point I begin my sparge. I drain directly from my hot liquor tank over the grain bed, usually through a 3/4" hose which flows on top of an upside down colander. The colander is used to get a more evenly distributed and slower stream of hot liquor over the grain bed. As I am sparging, wort is being drained out of the bottom of the mashtun into the brew kettle. I try to keep the liquid level in the mashtun within an inch above the top of the grain bed. So, I'll adjust the flows on both the hot liquor tank and the mashtun accordingly until I reach the right balance of flow. This way the grain bed is neither over-saturated or too dry. I am not sure if this technique, or my reasoning, is correct, but nonetheless, this is what I do (and please correct me if I'm wrong). So, I continue sparging until I reach my target pre-boil volume. By this time, I hope and pray that (mostly) everything I need out of the grains was rinsed through the grain bed and into the brew kettle.

And finally, some specific questions:

1. Is it okay that my mash is just sitting without any mixing or recirculating for the entire hour? Any recommended techniques to mix or recirculate during mash using my current igloo cooler setup?

2. Why recirculate the mash? Is it simply to achieve better clarity of the wort, or are there other reasons such as creating a better grain bed or mash temperature control?

3. Does my post-mash recirculating make sense? Will this help the grain bed or help rinse the sugars? A part of me finds it difficult to pour the fresh wort back on top of the grain bed because I would think that the first 10 gallons of wort is already full sugars, body, and flavor and you are risking the chance of losing them by pouring it back on top of the grain bed.

4. When sparging, is the velocity of the flow and the overall time it takes to sparge important? What is better - slower or faster?

5. Does my reasoning make sense to keep the water level right above the top of the grain bed during sparging?

6. At any point during the sparge, should I stop the flow of hot liquor, let the mashton run dry, and then continue the flow of hot liquor over the now dry grain bed? I can see a benefit to this, getting a full drain of the mash, but at the same time I am not sure if drying out the grain bed causes problems with the sparge.

Thanks in advance for any shared insight.
--
David J. Stein

One thing I notice already... "gently mix the mash w/ a spoon" I beat the hell out of my mash after I put it in, you want NO doughballs or areas where water isn't fully saturating the grains to get that sweet sticky wort... mixing doesn't need to be done more than at the start, imho, but others may correct me if I'm wrong. I then mash out, and readd my water for second round ( I just batch sparge) and let sit for 10 mins at higher temps w/ a recirc going (I have HERMS) but both initial strike water and addon sparge water is added and I stir the mash like mad to get it fully mixed w/ the water, I too have inconsistency though, I sometimes get 75% others 85% and would like to consistently get 85%, and am trying to find out what in my process is not working...

Hope you find your lil gremlins and beat them silly

Also, as Pompeii said, stir the grain bed very well when doughing in. You want the grain and water to be thoroughly mixed, and the grain thoroughly wetted, and to ensure the temperature is uniform throughout. Check the temperature in a few places, and stir until it's the same everywhere you check.

When you drain your wort, you're pouring it back into the MLT? Is that what you mean by recirculate? Why? There isn't any reason to do that, and I'm wondering if you're causing, though diffusion, the sugars that are dissolved in the wort to get "stuck" again to the grain. I just don't understand that step at all. I also wonder if you're dropping the temperature during this recirculation, but maybe I just don't understand what you're doing. It does sound like you're compacting the grain bed, though. That will make it much more difficult to get a good sparge. Your question about recirculating the finished wort has me scratching my head. I have no idea why you'd do that, or what it would accomplish. I think it's hurting your efficiency, since you'd be putting the sugars back into the mashtun, and compacting the grainbed at the same time.

You will want to recirculate the first couple of quarts back into the grain bed, since the grain bed works as a filter and will filter out the grain particles. But after the wort starts running clear, don't put it back in the grain bed. Drain it out, to the level you described, and start your sparge.

Your description of the sparge sounds fine.

1. It is perfectly acceptable for you to just leave the mash sitting there without mixing or recirculating for an hour. The more your cooler is open, the more heat you are going to lose. But it isn't going to hurt anything to open it once about half way through to take the temperature and give it a stir.

2. Why recirculate the mash? This is called vorlaufing. It does two things, both of which you have already hit on. You are basically sucking all that grain down into a compact bed that will act as a sort of self filter and that, in turn, will filter all the little bits out and cause your wort to be clear. I think 10 gallons of vorlaufing is excessive. You only need to vorlauf until the wort that is draining out the bottom is clear. I have found that this normally occurs within 1.5-2 gallons. Your system, grind and recipe may cause you to have to vorlauf more or less.

3. Again, you only need to vorlauf until the wort runs clear. Any more doesn't help, it probably doesn't hurt either.

4. Yes, when sparging the rate is important. Slower is better. You should probably aim for a total sparge time of 1 hour. If you miss that by 10 minutes in either direction you aren't going to hurt anything.

5. In general, you should try to keep about two inches of liquid on top of the grain when sparging. Less than that and I've found that there isn't enough pressure and I get stuck sparges or just really slow trickles. More than that and I find that there is still lots of sugars left in the top water at the end of the sparge. Your system may vary. I use one of those upright round coolers. With a rectangular cooler, you may find that batch sparging is generally faster and more efficient.

6. There is really no point to this that I can see, but this is how the typical batch sparge would proceed. Vorlauf --> drain --> Add first batch sparge volume and stir vigorously --> vorlauf --> drain and repeat once. The point of fly sparging is having a constant slow flow from top to bottom with hot sparge water slowly trickling down and flushing out the sugars. Letting it drain completely just means that your mash is going to cool down and congeal and those sugars are going to be harder to get into solution.

pompeiisneaks said:

One thing I notice already... "gently mix the mash w/ a spoon" I beat the hell out of my mash after I put it in, you want NO doughballs or areas where water isn't fully saturating the grains to get that sweet sticky wort... mixing doesn't need to be done more than at the start, imho, but others may correct me if I'm wrong. I then mash out, and readd my water for second round ( I just batch sparge) and let sit for 10 mins at higher temps w/ a recirc going (I have HERMS) but both initial strike water and addon sparge water is added and I stir the mash like mad to get it fully mixed w/ the water, I too have inconsistency though, I sometimes get 75% others 85% and would like to consistently get 85%, and am trying to find out what in my process is not working...

Hope you find your lil gremlins and beat them silly

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Thanks! The reason I gently mix the mash is because I have to avoid dislodging the draining manifold at the bottom of the mashtun. If it gets dislodged, the drainage becomes a serious problem and the only way to fix it is to stick my hands down into the 150ish degree mash. Luckily I haven't had to do that yet. I agree fully that it's ideal to thoroughly mix the mash to ensure no doughballs or dry spots. I am usually able to avoid this by pouring the hot liquor into the mashtun at the same rate as the grains. It does a good job of mixing it all together.

I am also trying to get my consistency to 85%. Last weekend I brewed two 10-gallon batches. One was 83% efficient and the other was 73%. I'm so used to the inconsistency at this point that I don't get to worked up about it.

Anyway, thanks for the reply and happy brewing!

I don't understand this focus on efficiency. The more sugars you are extracting out of the grain the more chance that you are going to extract other flavors too. Some may be good, but some probably are going to be bad. On the commercial scale I can see why increasing your average efficiency by a percentage point or two might make huge financial sense, but for the homebrewer? We are talking a savings of a few cents to a dollar a batch?

Personally, I set all my recipes at 70-75% efficiency and 6 gallons. If I have a bad day or miss my numbers I have some cushion. If I overshoot my efficiency, well I add water to get to my target SG and then either toss or freeze the extra wort for a starter. I just don't find its worth the hassle or energy to try to extract every last single spec of sugar out of the grain. I mean, you could just keep sparging and collecting wort until the gravity of the liquid coming out of the bottom of your grain is 1.000 thus ensuring every last possible sugar has been collected and then boil it all down to the appropriate volume, but I think we would all agree that would be a ton of wasted effort.

I have hit 85% efficiency before, but not on purpose and its not something I try to repeat.

YooperBrew said:

Also, as Pompeii said, stir the grain bed very well when doughing in. You want the grain and water to be thoroughly mixed, and the grain thoroughly wetted, and to ensure the temperature is uniform throughout. Check the temperature in a few places, and stir until it's the same everywhere you check.

When you drain your wort, you're pouring it back into the MLT? Is that what you mean by recirculate? Why? There isn't any reason to do that, and I'm wondering if you're causing, though diffusion, the sugars that are dissolved in the wort to get "stuck" again to the grain. I just don't understand that step at all. I also wonder if you're dropping the temperature during this recirculation, but maybe I just don't understand what you're doing. It does sound like you're compacting the grain bed, though. That will make it much more difficult to get a good sparge. Your question about recirculating the finished wort has me scratching my head. I have no idea why you'd do that, or what it would accomplish. I think it's hurting your efficiency, since you'd be putting the sugars back into the mashtun, and compacting the grainbed at the same time.

You will want to recirculate the first couple of quarts back into the grain bed, since the grain bed works as a filter and will filter out the grain particles. But after the wort starts running clear, don't put it back in the grain bed. Drain it out, to the level you described, and start your sparge.

Your description of the sparge sounds fine.

Click to expand...

Yes, I have been pouring the first 10-or-so gallons of wort back onto the MLT and coining that as my "recirculation". Already, from your response and NYCHomebrewer's, I have learned that this is not necessary. All I need to recirc or "vorlauf" is the first bit until the wort is running clear. Good to know. I was doing my recirculation process in hopes to create a better grain bet for the sparge, but, from what you're saying, it is actually hurting the grain bed.

Well, your response is most helpful and very appreciated. I'll let you know how things go for the next brew.

NYCHomebrewer said:

1. It is perfectly acceptable for you to just leave the mash sitting there without mixing or recirculating for an hour. The more your cooler is open, the more heat you are going to lose. But it isn't going to hurt anything to open it once about half way through to take the temperature and give it a stir.

2. Why recirculate the mash? This is called vorlaufing. It does two things, both of which you have already hit on. You are basically sucking all that grain down into a compact bed that will act as a sort of self filter and that, in turn, will filter all the little bits out and cause your wort to be clear. I think 10 gallons of vorlaufing is excessive. You only need to vorlauf until the wort that is draining out the bottom is clear. I have found that this normally occurs within 1.5-2 gallons. Your system, grind and recipe may cause you to have to vorlauf more or less.

3. Again, you only need to vorlauf until the wort runs clear. Any more doesn't help, it probably doesn't hurt either.

4. Yes, when sparging the rate is important. Slower is better. You should probably aim for a total sparge time of 1 hour. If you miss that by 10 minutes in either direction you aren't going to hurt anything.

5. In general, you should try to keep about two inches of liquid on top of the grain when sparging. Less than that and I've found that there isn't enough pressure and I get stuck sparges or just really slow trickles. More than that and I find that there is still lots of sugars left in the top water at the end of the sparge. Your system may vary. I use one of those upright round coolers. With a rectangular cooler, you may find that batch sparging is generally faster and more efficient.

6. There is really no point to this that I can see, but this is how the typical batch sparge would proceed. Vorlauf --> drain --> Add first batch sparge volume and stir vigorously --> vorlauf --> drain and repeat once. The point of fly sparging is having a constant slow flow from top to bottom with hot sparge water slowly trickling down and flushing out the sugars. Letting it drain completely just means that your mash is going to cool down and congeal and those sugars are going to be harder to get into solution.

Click to expand...

NYCHomebrewer said:

I don't understand this focus on efficiency. The more sugars you are extracting out of the grain the more chance that you are going to extract other flavors too. Some may be good, but some probably are going to be bad. On the commercial scale I can see why increasing your average efficiency by a percentage point or two might make huge financial sense, but for the homebrewer? We are talking a savings of a few cents to a dollar a batch?

Personally, I set all my recipes at 70-75% efficiency and 6 gallons. If I have a bad day or miss my numbers I have some cushion. If I overshoot my efficiency, well I add water to get to my target SG and then either toss or freeze the extra wort for a starter. I just don't find its worth the hassle or energy to try to extract every last single spec of sugar out of the grain. I mean, you could just keep sparging and collecting wort until the gravity of the liquid coming out of the bottom of your grain is 1.000 thus ensuring every last possible sugar has been collected and then boil it all down to the appropriate volume, but I think we would all agree that would be a ton of wasted effort.

I have hit 85% efficiency before, but not on purpose and its not something I try to repeat.

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NYCHomebrewer,

Your responses are very insightful and much appreciated. Your in-depth answers to my original questions are a tremendous help. I think I am in a much better place moving forward.

In regard to efficiency, I suppose I have been looking at it more as a direct correlation to the quality of my mash/sparge system. So, the better my efficiency, the better my system. However, I do see your point. I suppose it's really just important to hit your target efficiency, regardless of how high or low it is.

I used to always assume 70-75% efficiency as well, however, lately for my lighter ales (pale-->amber/red), I have been assuming an efficiency of 80%. My reasoning behind this is that the higher my target efficiency is, the less grains I end up using in the recipe. The less grains I am using in the recipe, the less my chances are of overshooting my gravity and having a malt character/ABV % that is too high. And I figured better to hit lower than the target efficiency because I can make up for any lack of sugars with a honey/sucrose addition to the boil.

The other side of the coin, which is more your stance, is that if you set the recipes at a low(er) efficiency, around 70-75%, and you end up overshooting, you can dilute the wort with water to reach the desired SG. If you undershoot the gravity, then you can also make up for any lack of sugars with a honey/sucrose addition to the boil. I can see both viewpoints, but it's hard for me to decide which is the better/safer/smarter way to go about it.

Any thoughts?

Once you get a good system, and get comfortable with it, you almost always hit your efficiency.

The number itself doesn't really matter. In my case, I get 72%. That's fine, because I can make any recipe and any beer and plan on an efficiency of +/- 72%.

The type of equipment doesn't matter- you can create great wort with a bucket system, and bad beer with a HERMS. What matters is the techniques you use, like the temperature of the wort, not oversparging, paying attention to pH, etc.

I'd suggest doing just what you seem to be doing- evaluating each process and finetuning your methods. Questioning the recirculation, and even if you want to batch vs. fly sparge is a great step.

I guess what is most important is to set the efficiency for your recipes that you usually achieve. If your system gets you an 80% on average, that is what you should probably set your target efficiency at.

What I don't think is particularly helpful is constant tweaking of your brewing system in order to obtain ever higher and higher levels of efficiency approaching the theoretical maximum. In my opinion, that is wasted energy that could be better focused on brewing another batch of beer!

Efficiency does have its place. If you are averaging 50% efficiency, then you should probably take a good long look at how you brew and see where you can tighten things up in your process rather than doubling the grain bill in all your recipes. Especially since 75-80% efficiency is so easy to get. Consistency is the key. Slight increases in efficiency will naturally follow as you get more comfortable with your process. And once you have your system dialed in you will start making consistently good beers regardless of what your actual efficiency is.

And yet... this hobby attracts all kinds of people who appreciate it for very different reasons. We wouldn't have batch sparging or BIAB if some people out there didn't watch their efficiencies and experiment in different methods and prove that they could make great beers doing unconventional things. Who knows, maybe a new specially designed manifold or process will allow us all to make beers at 90% efficiency someday. Although I'd guess that sort of efficiency is going to stem from a change in the grain genetics or malting process.

YooperBrew said:

Once you get a good system, and get comfortable with it, you almost always hit your efficiency.

The number itself doesn't really matter. In my case, I get 72%. That's fine, because I can make any recipe and any beer and plan on an efficiency of +/- 72%.

The type of equipment doesn't matter- you can create great wort with a bucket system, and bad beer with a HERMS. What matters is the techniques you use, like the temperature of the wort, not oversparging, paying attention to pH, etc.

I'd suggest doing just what you seem to be doing- evaluating each process and finetuning your methods. Questioning the recirculation, and even if you want to batch vs. fly sparge is a great step.

Click to expand...

I agree YooperBrew. Thanks for the advice. I haven't yet done my research on PH, and don't quite understand it, so I think that is what I will look into next.

For quite sometime I was baffled by my efficiency inconsistencies. I thought it was my process and/or equipment that was somehow causing issues. I later discovered the issues were caused by the ingredients and differing maltsters. Batches with Maris Otter was getting me 90%+ efficiency while Great Western 2-row was getting me 77-79%. The extraction points for these grains in my software program were set to the same value (in actuality the Maris Otter should have a higher extraction). So, it turns out my efficiency wasn't deficient in the Maris Otter recipes, the extraction value was wrong. Just something to think about as you consider your variables.

That explains so much on a couple of recent brews! Maybe 3 months ago the LHBS ran out of American 2 Row which I wanted for a recipe. Being a flexible guy I told them to sub MO. While I'm generally very consistent, I overshot my SG target by a considerable amount. The next two brews I was right on target, using american 2-row. Then this last weekend I again overshot my target by a considerable amount.

The MO must be the culprit.

NYCHomebrewer said:

That explains so much on a couple of recent brews! Maybe 3 months ago the LHBS ran out of American 2 Row which I wanted for a recipe. Being a flexible guy I told them to sub MO. While I'm generally very consistent, I overshot my SG target by a considerable amount. The next two brews I was right on target, using american 2-row. Then this last weekend I again overshot my target by a considerable amount.

The MO must be the culprit.

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Beyond just the extraction value, the MO grains are more plump. This causes the crush to be more effective. When you consider the size of the grain and the extraction value, you can see why it can boost your OG so much. The good news is that this is easily fixed and means that your efficiency is not the problem. :fro:

You start by saying "my mash is never consistent and always lacking in efficiency."
You continue with "So, I first get my hot liquor up to temp (~165-170 F) while meanwhile preparing and grinding the grains. Once the hot liquor is ready, I pour it quickly into the mashtun with the grains, trying my best to pour the water and grains at the same rate to get a good mix. After this transfer, and some gentle mixing with a brew spoon, the temperature of the mash is typically around 152-156 degrees.
I think that those two statements go a long way to explaining the inconsistency.
The "gentle mixing" has already been covered, so I won't repeat that except to say that I agree, and that will help with efficiency and consistency.
The next thing, is that you heat the strike water to 165 - 170, and end up with a mash temp of 152 - 156. That is a very wide range, and will affect consistency.
You should use a strike temp calculator such as comes with Beersmith, or Promash, or http://www.rackers.org/calcs.shtml. If the calculator doesn't take the thermal mass of the mash tun into consideration, you should pre-heat the mash tun before adding the grain and the water, and you should measure the temperature accurately. Many people, heat the strike water about 10 degrees higher than necessary and pour it into the mash tun (which heats it), and wait for it to cool to the required temperature. Stirring the water helps to cool it quickly. You do have an accurate thermometer don't you?
You didn't mention anything about the mash thickness. I usually use 1 qt water per lb grain. Most people here use more water per lb (about 1.25 - 1.5 qt / lb), but whatever you do, you should be consistent. If you are inconsistent, then your results will also be inconsistent.
As for efficiency, it has already been explained that you should adjust your efficiency to match what you achieve. If you improve your consistency, your efficiency will stabilize and make this easy.

Hope this helps.

-a.

First, if you want to control your process, you have to control your ingredients. I would suggest you secure a bulk supply of your base malt.

You may wish to try some of the different maltsters before you lock in your base grain. I would order in 10-20 lbs. from some of the various internet suppliers.

Try Rahr, Briess, Great Western or Gambrinus for American 2-row. Obtain malt analysis sheet from each purveyor and enter the information in your brewing software.

If you wish to use imported barley, make sure you note where it is grown and malted. Each field and maltster is a bit different. Crisp Marris Otter is not the same as Munton's Marris Otter. You should take note of this.

Each barley strain, grower and maltster puts their own mark on the end product. You should carefully examine the crush and vary the gap on your mill to obtain the best results for each vendor. You WILL have to change the gap for speciality grains from a different maltster to get the best extraction.

You should re-examine your vorlauf process. It might be worth it to invest in a pump to move the liquid from the bottom of your lauter tun to the top. It will speed up the process and you will be able to better maintain constant temperatures.

Wayne1 said:

First, if you want to control your process, you have to control your ingredients. I would suggest you secure a bulk supply of your base malt.

You may wish to try some of the different maltsters before you lock in your base grain. I would order in 10-20 lbs. from some of the various internet suppliers.

Try Rahr, Briess, Great Western or Gambrinus for American 2-row. Obtain malt analysis sheet from each purveyor and enter the information in your brewing software.

If you wish to use imported barley, make sure you note where it is grown and malted. Each field and maltster is a bit different. Crisp Marris Otter is not the same as Munton's Marris Otter. You should take note of this.

Each barley strain, grower and maltster puts their own mark on the end product. You should carefully examine the crush and vary the gap on your mill to obtain the best results for each vendor. You WILL have to change the gap for speciality grains from a different maltster to get the best extraction.

You should re-examine your vorlauf process. It might be worth it to invest in a pump to move the liquid from the bottom of your lauter tun to the top. It will speed up the process and you will be able to better maintain constant temperatures.

Click to expand...

Though that might seem obsessive and particular, that's some solid advice.